package prolog.builtins

import org.junit.jupiter.api.Assertions.assertEquals
import org.junit.jupiter.api.BeforeEach
import org.junit.jupiter.api.Nested
import org.junit.jupiter.api.Test
import org.junit.jupiter.params.ParameterizedTest
import org.junit.jupiter.params.provider.ValueSource
import prolog.Program
import prolog.ast.logic.Clause
import prolog.ast.logic.Fact
import prolog.ast.logic.Rule
import prolog.ast.terms.Atom
import prolog.ast.terms.Structure
import prolog.ast.terms.Variable
import kotlin.test.assertTrue

class DatabaseOperatorsTests {
    abstract class AssertTestsBase<T : Structure> {
        protected abstract fun createAssert(clause: Clause): Structure

        @BeforeEach
        fun setup() {
            Program.clear()
        }

        @ParameterizedTest
        @ValueSource(classes = [AssertA::class, AssertZ::class, Assert::class])
        fun `assert(fact atom)`(assertKind: Class<*>) {
            val fact = Fact(Atom("a"))
            createAssert(fact).satisfy(emptyMap())

            assertEquals(1, Program.internalDb.predicates.size, "Expected 1 predicate")
            assertEquals(fact, Program.internalDb.predicates["a/_"]!!.clauses[0])
        }

        @Test
        fun `assert(fact structure)`() {
            val fact = Fact(Structure(Atom("a"), listOf(Atom("b"))))
            createAssert(fact).satisfy(emptyMap())

            assertEquals(1, Program.internalDb.predicates.size, "Expected 1 predicate")
            assertEquals(fact, Program.internalDb.predicates["a/1"]!!.clauses[0])
        }

        @Test
        fun `assert(rule)`() {
            val rule = Rule(
                Structure(Atom("a"), listOf(Atom("b"))),
                Atom("c")
            )
            createAssert(rule).satisfy(emptyMap())

            assertEquals(1, Program.internalDb.predicates.size, "Expected 1 predicate")
            assertEquals(rule, Program.internalDb.predicates["a/1"]!!.clauses[0])
        }
    }

    @Nested
    class AssertTests : AssertTestsBase<Assert>() {
        override fun createAssert(clause: Clause): Structure {
            return Assert(clause)
        }
    }

    @Nested
    class AssertATests : AssertTestsBase<AssertA>() {
        override fun createAssert(clause: Clause): Structure {
            return AssertA(clause)
        }

        @Test
        fun `asserta adds to the beginning`() {
            val rule1 = Rule(
                Structure(Atom("a"), listOf(Atom("b"))),
                Atom("c")
            )
            val rule2 = Rule(
                Structure(Atom("a"), listOf(Atom("d"))),
                Atom("e")
            )
            AssertA(rule1).satisfy(emptyMap())
            AssertA(rule2).satisfy(emptyMap())

            assertEquals(1, Program.internalDb.predicates.size, "Expected 1 predicate")
            assertEquals(rule2, Program.internalDb.predicates["a/1"]!!.clauses[0])
            assertEquals(rule1, Program.internalDb.predicates["a/1"]!!.clauses[1])
        }
    }

    @Nested
    class AssertZTests : AssertTestsBase<AssertZ>() {
        override fun createAssert(clause: Clause): Structure {
            return AssertZ(clause)
        }

        @Test
        fun `assertz adds to the end`() {
            val rule1 = Rule(
                Structure(Atom("a"), listOf(Atom("b"))),
                Atom("c")
            )
            val rule2 = Rule(
                Structure(Atom("a"), listOf(Atom("d"))),
                Atom("e")
            )
            AssertZ(rule1).satisfy(emptyMap())
            AssertZ(rule2).satisfy(emptyMap())

            assertEquals(1, Program.internalDb.predicates.size, "Expected 1 predicate")
            assertEquals(rule1, Program.internalDb.predicates["a/1"]!!.clauses[0])
            assertEquals(rule2, Program.internalDb.predicates["a/1"]!!.clauses[1])
        }
    }

    @Test
    fun `custom example`() {
        var query = Structure(Atom("likes"), listOf(Atom("alice"), Atom("pizza")))

        var result = Program.query(query).toList()
        assertEquals(0, result.size, "Expected 0 results")

        var assert: Structure = Assert(Fact(query))
        assert.satisfy(emptyMap())

        result = Program.query(query).toList()
        assertEquals(1, result.size, "Expected 1 result")
        assertTrue(result[0].getOrNull()!!.isEmpty())

        assert = AssertZ(Fact(Structure(Atom("likes"), listOf(Atom("bob"), Atom("sushi")))))
        assert.satisfy(emptyMap())

        query = Structure(Atom("likes"), listOf(Atom("bob"), Variable("X")))

        result = Program.query(query).toList()
        assertEquals(1, result.size, "Expected 1 result")
        assertTrue(result[0].isSuccess, "Expected success")
        assertEquals(Atom("sushi"), result[0].getOrNull()!![Variable("X")], "Expected sushi")

        query = Structure(Atom("likes"), listOf(Variable("X"), Variable("Y")))

        result = Program.query(query).toList()
        assertEquals(2, result.size, "Expected 2 results")
        assertTrue(result[0].isSuccess, "Expected success")
        var result0 = result[0].getOrNull()!!
        assertEquals(Atom("alice"), result0[Variable("X")], "Expected alice")
        assertEquals(Atom("pizza"), result0[Variable("Y")], "Expected pizza")
        assertTrue(result[1].isSuccess, "Expected success")
        var result1 = result[1].getOrNull()!!
        assertEquals(Atom("bob"), result1[Variable("X")], "Expected bob")
        assertEquals(Atom("sushi"), result1[Variable("Y")], "Expected sushi")

        assert = AssertA(Rule(
            Structure(Atom("likes"), listOf(Variable("X"), Atom("italian"))),
            Structure(Atom("likes"), listOf(Variable("X"), Atom("pizza")))
        ))
        assert.satisfy(emptyMap())

        result = Program.query(query).toList()
        assertEquals(3, result.size, "Expected 3 results")
        assertTrue(result[0].isSuccess, "Expected success")
        result0 = result[0].getOrNull()!!
        assertEquals(Atom("alice"), result0[Variable("X")], "Expected alice")
        assertEquals(Atom("italian"), result0[Variable("Y")], "Expected italian")
        assertTrue(result[1].isSuccess, "Expected success")
        result1 = result[1].getOrNull()!!
        assertEquals(Atom("alice"), result1[Variable("X")], "Expected alice")
        assertEquals(Atom("pizza"), result1[Variable("Y")], "Expected pizza")
        assertTrue(result[2].isSuccess, "Expected success")
        val result2 = result[2].getOrNull()!!
        assertEquals(Atom("bob"), result2[Variable("X")], "Expected bob")
        assertEquals(Atom("sushi"), result2[Variable("Y")], "Expected sushi")
    }
}